Biomaterial Database

The ribosomal RNA genes of Locusta migratoria: copy number and evidence for underreplication in a polyploid tissue. 1985

M Oishi, and J Locke, and G R Wyatt

From libraries of Locusta migratoria genomic DNA in bacteriophage lambda, clones have been isolated that hybridize with one or both of the 18S and 28S components of locust rRNA. Six clones studied show common patterns of restriction sites in the coding sequences and some include an intron in the 28S region. Subcloned sequences from within the 18S and 28S coding regions were used as probes in dot hybridization assays of the rRNA gene copy number in DNA prepared from several locust tissues and stages. The 18S and 28S probes gave similar results, showing about 4000 copies/haploid genome in testis, embryo, and fat body from larvae and immature adults of both sexes. This is by far the greatest rRNA gene copy number yet reported for any insect. DNA from reproductively mature adult female fat body showed a consistent reduction in the copy number by about one-third. Mature adult male fat body DNA showed no significant reduction in the copy number. It therefore appears that the final round of DNA replication in the adult female fat body, which produces 8-ploid and 16-ploid cells active in vitellogenin synthesis, involves underreplication of rDNA.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004275	DNA, Ribosomal	DNA sequences encoding RIBOSOMAL RNA and the segments of DNA separating the individual ribosomal RNA genes, referred to as RIBOSOMAL SPACER DNA.	Ribosomal DNA,rDNA
D005260	Female		Females
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D006110	Grasshoppers	Plant-eating orthopterans having hindlegs adapted for jumping. There are two main families: Acrididae and Romaleidae. Some of the more common genera are: Melanoplus, the most common grasshopper; Conocephalus, the eastern meadow grasshopper; and Pterophylla, the true katydid.	Acrididae,Locusts,Romaleidae,Grasshopper,Locust
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012335	RNA, Ribosomal	The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)	Ribosomal RNA,15S RNA,RNA, 15S